Filed with the Securities and Exchange Commission on May 16, 2025

1933 Act Registration File No. 033-20827

1940 Act Registration File No. 811-05518

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 [ X ]

Pre-Effective Amendment No.		[     ]
Post-Effective Amendment No.	351	[ X ]

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 [ X ]

Amendment No. 356 [ X ]

(Check appropriate box or boxes.)

THE RBB FUND, INC.

(Exact Name of Registrant as Specified in Charter)

615 East Michigan Street

Milwaukee, Wisconsin 53202

(Address of Principal Executive Offices, including Zip Code)

Registrant’s Telephone Number, including Area Code: (609) 731-6256

Copies to:

STEVEN PLUMP	JILLIAN BOSMANN, ESQUIRE
The RBB Fund, Inc.	Faegre Drinker Biddle & Reath LLP
615 East Michigan Street	One Logan Square, Suite 2000
Milwaukee, Wisconsin 53202	Philadelphia, Pennsylvania 19103-6996

It is proposed that this filing will become effective (check appropriate box) [ ] immediately upon filing pursuant to paragraph (b)

[	X	]	on May 30, 2025 pursuant to paragraph (b)
[		]	60 days after filing pursuant to paragraph (a)(1)
[		]	on (date) pursuant to paragraph (a)(1)
[		]	75 days after filing pursuant to paragraph (a)(2)
[		]	on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

[ X ] This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

EXPLANATORY NOTE

Designation of New Effective Date for Previously Filed Post-Effective Amendment

Post-Effective Amendment No. 338 (the “Amendment”) was filed pursuant to Rule 485(a)(2) under the Securities Act of 1933, as amended (the “1933 Act”), on January 15, 2025 and pursuant to Rule 485(a)(2) would have become effective on March 31, 2025.

Post-Effective Amendment No. 343 was filed pursuant to Rule 485(b)(1)(iii) under the 1933 Act on March 28, 2025 for the sole purpose of extending the date upon which the Amendment was to become effective to April 4, 2025.

Post-Effective Amendment No. 344 was filed pursuant to Rule 485(b)(1)(iii) under the 1933 Act on April 4, 2025 for the sole purpose of extending the date upon which the Amendment was to become effective to April 18, 2025.

Post-Effective Amendment No. 347 was filed pursuant to Rule 485(b)(1)(iii) under the 1933 Act on April 18, 2025 for the sole purpose of extending the date upon which the Amendment was to become effective to May 2, 2025 with respect to the F/m High Beta High Yield ETF, F/m High Quality High Yield ETF, F/m Short Duration Quality High Yield ETF, F/m Senior Secured High Yield ETF, F/m U.S. Treasury 3-Month Bill Institutional ETF, F/m Leveraged U.S. Treasury 3-Month Bill ETF, F/m Current Coupon Mortgage-Backed Securities ETF, F/m Short Duration High Coupon Tax-Free Municipal ETF, F/m Small Cap Core ETF, F/m Small Cap Growth ETF, and F/m SMID Equity ETF.

Post-Effective Amendment No. 348 was filed pursuant to Rule 485(b)(1)(iii) under the 1933 Act on May 1, 2025 for the sole purpose of extending the date upon which the Amendment was to become effective to May 16, 2025 with respect to the F/m High Beta High Yield ETF, F/m High Quality High Yield ETF, F/m Short Duration Quality High Yield ETF, F/m Senior Secured High Yield ETF, F/m U.S. Treasury 3-Month Bill Institutional ETF, F/m Leveraged U.S. Treasury 3-Month Bill ETF, F/m Current Coupon Mortgage-Backed Securities ETF, F/m Short Duration High Coupon Tax-Free Municipal ETF, F/m Small Cap Core ETF, F/m Small Cap Growth ETF, and F/m SMID Equity ETF.

This Post-Effective Amendment No. 351 is being filed pursuant to Rule 485(b)(1)(iii) under the 1933 Act for the sole purpose of designating May 30, 2025 as the new date upon which the Amendment shall become effective with respect to the F/m Long-Term Treasury Inflation-Protected Security (TIPS) ETF (listed in the Amendment as F/m Leveraged U.S. Treasury 3-Month Bill).

This Post-Effective Amendment No. 351 incorporates by reference the information contained in Parts A, B and C of the Amendment with respect to the F/m Long-Term Treasury Inflation-Protected Security (TIPS) ETF (listed in the Amendment as F/m Leveraged U.S. Treasury 3-Month Bill).

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended (the “1933 Act”), and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness of this Post-Effective Amendment to its Registration Statement under Rule 485(b) under the 1933 Act and has duly caused this Post-Effective Amendment to its Registration Statement to be signed on its behalf by the undersigned, thereto duly authorized, in the City of Short Hills and State of New Jersey on May 16, 2025.

THE RBB FUND, INC.

By: /s/ Steven Plump

Steven Plump

President

Pursuant to the requirements of the 1933 Act, this Amendment to Registrant’s Registration Statement has been signed below by the following persons in the capacities and on the date indicated.

SIGNATURE TITLE DATE

/s/ Steven Plump	President (Principal Executive Officer)	May 16, 2025
Steven Plump
	Chief Financial Officer (Principal	May 16, 2025
/s/ James G. Shaw	Financial and Accounting Officer)
James G. Shaw
*Gregory P. Chandler	Director	May 16, 2025
Gregory P. Chandler
*Lisa A. Dolly	Director	May 16, 2025
Lisa A. Dolly
*Nicholas A. Giordano	Director	May 16, 2025
Nicholas A. Giordano
*Arnold M. Reichman	Director	May 16, 2025
Arnold M. Reichman
*Robert Sablowsky	Director	May 16, 2025
Robert Sablowsky
*Brian T. Shea	Director	May 16, 2025
Brian T. Shea
*Martha Tirinnanzi	Director	May 16, 2025
Martha Tirinnanzi

*By: /s/ James G. Shaw

James G. Shaw

Attorney-in-Fact

THE RBB FUND, INC.

(the “Company”)

THE RBB FUND TRUST

(the “Trust”)

POWER OF ATTORNEY

Know All Men by These Presents, that the undersigned, Gregory P. Chandler, hereby constitutes and appoints Jillian L. Bosmann, Michael P. Malloy, Edward Paz, Steven Plump, and James G. Shaw his true and lawful attorneys, to execute in his name, place, and stead, in his capacity as Director/Trustee or officer, or both, of the Company and of the Trust, the Registration Statement and any amendments thereto and all instruments necessary or incidental in connection therewith, and to file the same with the Securities and Exchange Commission; and said attorneys shall have full power and authority to do and perform in his name and on his behalf, in any and all capacities, every act whatsoever requisite or necessary to be done in the premises, as fully and to all intents and purposes as he might or could do in person, said acts of said attorneys being hereby ratified and approved.

DATED:	February 13, 2024
	/s/ Gregory P. Chandler
	Gregory P. Chandler

THE RBB FUND, INC.

(the “Company”)

THE RBB FUND TRUST

(the “Trust”)

POWER OF ATTORNEY

Know All Men by These Presents, that the undersigned, Lisa A. Dolly, hereby constitutes and appoints Jillian L. Bosmann, Michael P. Malloy, Edward Paz, Steven Plump, and James G. Shaw her true and lawful attorneys, to execute in her name, place, and stead, in her capacity as Director/Trustee or officer, or both, of the Company and of the Trust, the Registration Statement and any amendments thereto and all instruments necessary or incidental in connection therewith, and to file the same with the Securities and Exchange Commission; and said attorneys shall have full power and authority to do and perform in her name and on her behalf, in any and all capacities, every act whatsoever requisite or necessary to be done in the premises, as fully and to all intents and purposes as she might or could do in person, said acts of said attorneys being hereby ratified and approved.

DATED:	February 13, 2024
	/s/ Lisa A. Dolly
	Lisa A. Dolly

THE RBB FUND, INC.

(the “Company”)

THE RBB FUND TRUST

(the “Trust”)

POWER OF ATTORNEY

Know All Men by These Presents, that the undersigned, Nicholas A. Giordano, hereby constitutes and appoints Jillian L. Bosmann, Michael P. Malloy, Edward Paz, Steven Plump, and James G. Shaw his true and lawful attorneys, to execute in his name, place, and stead, in his capacity as Director/Trustee or officer, or both, of the Company and of the Trust, the Registration Statement and any amendments thereto and all instruments necessary or incidental in connection therewith, and to file the same with the Securities and Exchange Commission; and said attorneys shall have full power and authority to do and perform in his name and on his behalf, in any and all capacities, every act whatsoever requisite or necessary to be done in the premises, as fully and to all intents and purposes as he might or could do in person, said acts of said attorneys being hereby ratified and approved.

DATED:	February 13, 2024
	/s/ Nicholas A. Giordano
	Nicholas A. Giordano

THE RBB FUND, INC.

(the “Company”)

THE RBB FUND TRUST

(the “Trust”)

POWER OF ATTORNEY

Know All Men by These Presents, that the undersigned, Arnold M. Reichman, hereby constitutes and appoints Jillian L. Bosmann, Michael P. Malloy, Edward Paz, Steven Plump, and James G. Shaw his true and lawful attorneys, to execute in his name, place, and stead, in his capacity as Director/Trustee or officer, or both, of the Company and of the Trust, the Registration Statement and any amendments thereto and all instruments necessary or incidental in connection therewith, and to file the same with the Securities and Exchange Commission; and said attorneys shall have full power and authority to do and perform in his name and on his behalf, in any and all capacities, every act whatsoever requisite or necessary to be done in the premises, as fully and to all intents and purposes as he might or could do in person, said acts of said attorneys being hereby ratified and approved.

DATED:	February 13, 2024
	/s/ Arnold M. Reichman
	Arnold M. Reichman

THE RBB FUND, INC.

(the “Company”)

THE RBB FUND TRUST

(the “Trust”)

POWER OF ATTORNEY

Know All Men by These Presents, that the undersigned, Robert Sablowsky, hereby constitutes and appoints Jillian L. Bosmann, Michael P. Malloy, Edward Paz, Steven Plump, and James G. Shaw his true and lawful attorneys, to execute in his name, place, and stead, in his capacity as Director/Trustee or officer, or both, of the Company and of the Trust, the Registration Statement and any amendments thereto and all instruments necessary or incidental in connection therewith, and to file the same with the Securities and Exchange Commission; and said attorneys shall have full power and authority to do and perform in his name and on his behalf, in any and all capacities, every act whatsoever requisite or necessary to be done in the premises, as fully and to all intents and purposes as he might or could do in person, said acts of said attorneys being hereby ratified and approved.

DATED:	February 13, 2024
	/s/ Robert Sablowsky
	Robert Sablowsky

THE RBB FUND, INC.

(the “Company”)

THE RBB FUND TRUST

(the “Trust”)

POWER OF ATTORNEY

Know All Men by These Presents, that the undersigned, Brian T. Shea, hereby constitutes and appoints Jillian L. Bosmann, Michael P. Malloy, Edward Paz, Steven Plump, and James G. Shaw his true and lawful attorneys, to execute in his name, place, and stead, in his capacity as Director/Trustee or officer, or both, of the Company and of the Trust, the Registration Statement and any amendments thereto and all instruments necessary or incidental in connection therewith, and to file the same with the Securities and Exchange Commission; and said attorneys shall have full power and authority to do and perform in his name and on his behalf, in any and all capacities, every act whatsoever requisite or necessary to be done in the premises, as fully and to all intents and purposes as he might or could do in person, said acts of said attorneys being hereby ratified and approved.

DATED:	February 13, 2024
	/s/ Brian T. Shea
	Brian T. Shea

THE RBB FUND, INC.

(the “Company”)

THE RBB FUND TRUST

(the “Trust”)

POWER OF ATTORNEY

Know All Men by These Presents, that the undersigned, Martha A. Tirinnanzi, hereby constitutes and appoints Jillian L. Bosmann, Michael P. Malloy, Edward Paz, Steven Plump, and James G. Shaw her true and lawful attorneys, to execute in her name, place, and stead, in her capacity as Director/Trustee or officer, or both, of the Company and of the Trust, the Registration Statement and any amendments thereto and all instruments necessary or incidental in connection therewith, and to file the same with the Securities and Exchange Commission; and said attorneys shall have full power and authority to do and perform in her name and on her behalf, in any and all capacities, every act whatsoever requisite or necessary to be done in the premises, as fully and to all intents and purposes as she might or could do in person, said acts of said attorneys being hereby ratified and approved.

DATED:	February 13, 2024
	/s/ Martha A. Tirinnanzi
	Martha A. Tirinnanzi